There has heretofore been suggested a fuel cell vehicle equipped with a fuel cell which is supplied with reactant gases (a fuel gas and an oxidation gas) and thereby generates electricity, together with a secondary cell such as a storage cell. An electric vehicle such as the fuel cell vehicle is generally equipped with an inverter provided between the fuel cell and an electric motor, and a controller which controls the inverter by pulse width modulation (PWM).
At present, there has been suggested a technique for measuring the speed of the fuel cell vehicle and the temperature of a switching element of the inverter, and increasing the carrier frequency of the inverter to a value higher than a normal value when measured values of both the speed and the temperature are equal to or less than predetermined thresholds (e.g. refer to Patent Document 1). It is known that the use of such a technique permits the reduction of both the overheating of the switching element and switching noise.